npj Microgravity最新文献

Future crewed expeditions beyond Earth will span multiple years, requiring a transition away from Earth-dependent pharmaceutical supply chains. Medications degrade more rapidly in space due to radiation exposure and storage constraints, while transporting large quantities of temperature-controlled biologics is logistically impractical. These challenges necessitate the development of self-sufficient, in-situ medical capabilities for deep space missions. This study evaluates the operational and clinical relevance (OCR) and recombinant production feasibility (RPF) of peptide therapeutics for on-demand manufacturing during long-duration spaceflight. Building on established astropharmacy databases and literature, 26 peptide-based medications relevant to spaceflight were identified and ranked using ten predefined OCR and RPF criteria. OCR criteria included regulatory status, shelf stability, storage requirements, NASA Human Research Roadmap risk/impact score, and purification requirements. RPF criteria included amino acid chain length, prior recombinant production, functional assay availability, dosing requirements, and post-translational modification complexity. All criteria were scored from 0-2 points. Teriparatide achieved the highest overall score (17/20), followed by abaloparatide and amylin (16/20). Several therapeutics, including angiotensin II, daptomycin, GLP-1 agonists, G-CSF, GM-CSF, and salmon calcitonin, also demonstrated potential (14/20). This study identifies peptide therapeutics as promising candidates for in-situ production and provides a structured framework to guide future astropharmacy development.

Boiling heat transfer is governed by a complex interplay between surface conditions and gravitational acceleration. To isolate the sole effects of gravity, we investigated the pool boiling characteristics of liquid nitrogen on atomically smooth silicon dioxide (SiO₂) surfaces under terrestrial (1-g) and reduced gravity ($0\pm 0.02$ g) conditions achieved via parabolic flight. Our results quantify a drastic reduction in the critical heat flux (CHF) in reduced gravity, decreasing from 16.15 W/cm² at 1-g to $5-6$ W/cm² at $\mu$-g due to the suppression of buoyancy. Conversely, we observed a distinct increase in the heat transfer coefficient (HTC) in the reduced gravity condition prior to CHF. By utilizing a surface with a maximum peak-to-valley height of $\approx 36.7$ nm and low contact angle hysteresis (< 10°), we confirm this HTC enhancement is an intrinsic response to the gravitational environment, decoupled from surface-defect-induced nucleation. These findings demonstrate that the influence of surface topography is significantly more prominent in reduced gravity than in terrestrial conditions, providing a critical baseline for rationalizing the design of cryogenic thermal management systems in space and quantum applications.

In-space manufacturing technologies are considered vital for enabling advanced space missions and addressing logistical limitations of space exploration. While additive manufacturing has progressed rapidly, it still falls short of delivering the ultra-smooth surfaces required for optical elements. Fluidic Shaping is a novel method that harnesses surface tension under microgravity to form optical components with exceptionally smooth surfaces. This study demonstrates the feasibility and potential of Fluidic Shaping as a method for manufacturing optical components in space through two experiments performed aboard the International Space Station (ISS) during the Ax-1 mission. The first experiment involved fabricating centimeter-scale polymer lenses, solidifying them via ultraviolet (UV) curing, and analyzing the resultant optics upon their return to Earth. While sub-nanometric surface smoothness was achieved, some polymer lenses displayed unexpected thermo-chemical deformations, indicating complex polymerization dynamics unique to the microgravity environment. In the second experiment, a 172 mm diameter water lens was deployed, confirming Fluidic Shaping's scalability and demonstrating basic optical functionality through image analysis. These experiments collectively underline the technique's relevance for both small-scale optics and large-aperture applications. Our results highlight critical considerations for future research, including optimizing polymerization processes and refining liquid-handling methods to advance practical, in-space optical manufacturing capabilities.

Spaceflight-associated neuro-ocular syndrome (SANS) poses significant ocular health risks in long-duration missions, yet its molecular mechanisms remain incompletely understood. Oxidative stress and apoptosis are candidate drivers, but their transcriptomic-phenotypic relationships in spaceflight-exposed retinal tissue have not been systematically characterized. We applied a machine learning ensemble to predict two ocular phenotypes: 4-hydroxynonenal (4-HNE) endothelial cell density as a marker of oxidative damage, and TUNEL endothelial cell density as a marker of apoptosis. In this observational study, we use transcriptomic data from a controlled experiment with ground control and spaceflown mice to predict these phenotypes. Gene Ontology pathway enrichment was performed using the most predictive genes for each phenotype. Genes predicting 4-HNE converge on membrane-associated pathways, photoreceptor modification, synaptic dysfunction, and extracellular matrix dysregulation, including B2m, Trf, Cnga1, mt-Nd1, Snap25, and Efemp1. Genes predicting TUNEL emphasize stress-induced apoptosis, rod photoreceptor degeneration, and endoplasmic reticulum dysfunction, with Ddit4, Nrl, Rom1, Reep6, and Gabarapl1 emerging as central regulators. Oxidative lipid peroxidation and apoptotic cell death represent complementary and molecularly distinct pathological mechanisms in spaceflight-exposed murine retinal tissue. The gene signatures provide a putative molecular framework for developing noninvasive biomarkers and therapeutic targets to monitor and protect astronaut visual health during long-duration and deep-space missions.

Space exploration presents environmental challenges, including microgravity, high-energy radiation, and extreme temperature changes. Accelerated aging in space provides a unique opportunity to study age-related neurodegenerative diseases. Tauopathies, such as Alzheimer's disease, are characterized by neurofibrillary tangles of hyperphosphorylated tau protein in the brain. We studied how time-averaged simulated microgravity (taSMG), which replicates space conditions, affects tauR406W-induced neurotoxicity in transgenic flies. Applying taSMG at an early stage of neurodegeneration reduced severe locomotion impairment in tauR406W-expressing flies. This protective effect was sustained, specific to the tau mutation, and dependent on the timing, duration, and severity of tau expression. Transcriptomic analysis revealed that taSMG normalizes gene expression related to the extracellular environment, innate immune response, and olfactory function. These results underscore gravity's role in modulating tauopathy and suggest that microgravity may potentially offer new therapeutic insights for neurodegenerative diseases.

Exposure to space environment disrupts the sensorimotor system due to adaptation to microgravity, leading to spatial disorientation, impaired coordination, and reduced postural control upon return to Earth. To simulate these effects, a six‑degree head‑down bed rest (HDBR) protocol was used. This randomized controlled trial examined whether exercise could mitigate declines in standing balance control following 14 days of HDBR. Twenty-two participants were assigned to either an exercise group, performing daily high-intensity interval training combined with resistance and aerobic exercise, or a non-exercising control group. Balance was assessed using the sensory organization test (SOT) and head-shake SOT, with outcomes including equilibrium score (ES), strategy analysis (SA), and vestibular-related measures (e.g., SOT-2M, SOT-5M). No between-group differences were observed in either ES or SA. However, when data were pooled, ES during SOT-2M was significantly decreased (p < 0.001), indicating greater instability under eyes-closed, head-shake conditions. Higher baseline ES during SOT-2M was associated with smaller declines post-HDBR, particularly in the exercise group. No effects of sex or age (55-65 years) were found. These findings suggest that exercise may not prevent balance declines after short-term HDBR and that baseline balance capacity may be associated with variability in individual responses. Clinical Trial Registration: NCT04964999 (2021-07-16).

Fungal pathogens are well-recognized biotic stressors for plants under terrestrial gravity and also pose risks to space crop production, but their effects on root-associated microbial networks under microgravity conditions remain poorly understood. Here, we profiled bacterial and fungal communities in wheat seedlings with or without Fusarium graminearum infection under normal gravity and simulated microgravity, and linked network properties to plant growth and hormone profiles. Although bacterial and fungal α-diversity showed no significant differences among treatments and Bray-Curtis β-diversity showed limited separation, co-occurrence networks revealed that infection disrupted bacterial-bacterial and bacterial-fungal networks more strongly under simulated microgravity than under normal gravity, whereas fungal-fungal networks were largely unchanged. Bacterial network characteristics explained more variation in plant performance than bacterial-fungal network characteristics. Structural equation modeling showed that simulated microgravity reduced endosphere bacterial network stability, which was positively associated with plant performance, especially jasmonic acid and cytokinin levels. Random forest analysis identified Paenibacillus and Microbacteriaceae-related taxa as key predictors of bacterial network stability. These findings support microbiome-based strategies to enhance plant resilience in space systems.

Long-duration spaceflight poses risks to musculoskeletal health, yet articular cartilage remains understudied. This review explores how microgravity and radiation compromise its homeostasis. Mechanical unloading suppresses chondrocyte metabolism and disrupts extracellular matrix equilibrium. Concurrently, radiation, oxidative stress, and immune activation induce DNA damage, mitochondrial dysfunction, and senescence, exacerbating matrix degradation. We assess physical, nutritional, and pharmacological countermeasures, highlighting the need for integrated strategies protecting joints during space exploration.

Communication delay during remote instruction of simple interrupted suturing was evaluated by randomizing participants to near real-time or 4-second delayed communication conditions. The delay group required more time to complete five sutures, with diminishing effect by the fifth suture. Instructor-reported cognitive workload was higher under delayed conditions, but suturing quality did not differ between groups. These findings suggest remote guidance is operationally feasible for non-medically trained individuals performing uncomplicated interventions.

Long-duration spaceflight produces structural, functional, and hemodynamic brain changes driven by microgravity, radiation, elevated CO2, and isolation. Consequences include Spaceflight-Associated Neuro-Ocular Syndrome, vestibular imbalance, orthostatic intolerance, and cognitive disturbance. We consolidate current evidence, present a cerebrovascular physiologic framework, and discuss emerging countermeasures-including lower body negative pressure, artificial gravity, advanced neuromonitoring, and synthetic torpor-needed to safeguard neurological health on exploration-class missions.